1. Field of the Invention
The present invention is related to electrical connectors, and more particularly is directed towards a new and improved modular jack adapted to serve as an interface between a standard modular plug and a printed circuit board.
2. Description of the Related Art
In recent years, a great deal of research and development has gone into providing miniature plugs and connectors for low voltage electronic applications. For example, in the telephone industry, increasing use is being made of modular plugs and connectors on the cords, base, handset and wall terminal block of a telephone system. Typical miniature plugs are described, for example, in U.S. Pat. Nos. 3,954,320 and 3,998,514, both in the name of Hardesty. As described therin, the telephone-type modular plug generally includes a dielectric housing having a free end for insertion into a mating modular jack, a cord input end having a cavity for receiving a multi-conductor cord, and a resilient locking tab integrally connected by a flexible hinge to the free end of the dielectric housing and extending obliquely rearwardly therefrom. The modular plug housing is also characterized by a terminal-receiving side having partitions which define side-by-side slots in communication with the cavity. Substantially flat, electrically conductive contact terminals are positioned within the slots and extend into the cavity, and the terminals include insulation-piercing tangs for making electrical engagement with associated conductors of the cord and upper edge portions for making electrical contact external to the plug.
It is desirable that such plugs and connectors be of rugged construction, compact size and high reliability, without requiring excessive manufacturing cost. Such plugs and connectors must also be able to be reliably, rapidly and automatically connected to cable and equipment components, respectively.
While the plugs and connectors provided in the past have been generally satisfactory, they suffer from one or more material drawbacks. For example, the miniature connector described in U.S. Pat. No. 3,850,497 is generally a rugged and compact unit. However, the complexity of the contact wire assembly utilized in the housing of the connector results in a high manufacturing cost due to the many components which must be assembled in a precision arrangement. Additionally, the interconnect portions of the contact wire assembly which protrude from the rear of the connector housing consist of flexible jumper wires having spade terminals or solder tabs for making connections to equipment components. Such terminals or tabs must be manually anchored or set in position for making the desired electrical connections. This procedure results in high labor costs when such connectors are mounted, for example, on printed circuit boards or to electronic or telephone components. A similar connector is described in U.S. Pat. No. 3,990,764, but suffers from the same deficiencies just described.
The aforementioned connectors also suffer from an additional major drawback. Regulations governing the size and spacing of standardized plugs have been adopted by the Federal Communications Commission. Consequently, any connector designed to mate with such plugs must have corresponding spacing between adjacent contact wires. However, printed circuit boards which are utilized extensively, for example, in digital data transmission equipment, sensing systems and the like, are presently manufactured with a conductor pad spacing that is different from the contact spacing on the above-described miniature telephone plugs and connectors. As a result, it has been necessary in the past to provide these connectors with jumper wires or special cables to connect the standard miniature telephone connector or jack to a printed circuit board.
Several U.S. patents, for example, U.S. Pat. No. 4,210,376, set forth miniature connectors for directly interfacing a modular plug with a printed circuit board. The connector of U.S. Pat. No. 4,210,376 comprises a housing having conductors extending over outside walls thereof. One end of each conductor is bent rearwardly into a plug receiving opening in the housing to form spring contact portions. The respective other ends of the conductors extend from the housing in alternating rows, and are properly spaced so as to be compatible with a printed circuit board. Nevertheless, the connector structure described in this patent necessitates a relatively long strip of stamped conductor to be utilized since the conductors are wrapped around the outside wall of the connector housing from the rear to the front thereof and are bent back into the plug receiving opening to form the spring contact portions.
U.S. Pat. No. 4,296,991 discloses what is known as a top mount connector. The conductors associated with this device are shorter than those of U.S. Pat. No. 4,210,376, but are still relatively long as they must extend over an outer wall of the connector housing to be bent rearwardly into the plug-receiving opening. The devices of both these patents require barbs or other retaining means associated with each conductor for retaining it in the housing.
The length of the conductors required for such connectors involves a considerable component cost, inasmuch as such conductors must generally be plated with a precious metal to meet industry standards of reliability, longevity and electrical contact integrity. The precious metal may comprise, for example, gold, and it therefore may be appreciated that it would be highly desirable to provide an improved connector which could utilize conductors of considerably reduced lengths as compared with previous designs. It would also be desirable to obviate the need for retaining barbs and the like, thus further reducing the cost of manufacture and assembly of the connector.
In my copending application Ser. No. 215,054, filed Dec. 10, 1980, which is specifically incorporated herein by reference, I have disclosed a connector which is a substantial improvement over those of the aforementioned patents. The connector of my copending application includes a plurality of conductors whose spring contact portions extend into the conductor housing from the rear of the plug-receiving opening. The spring contact portions of the conductors extend forwardly into the plug-receiving opening, toward the front wall of the housing. As compared with the printed circuit board connectors of the prior art, which required the conductors to extend to the front portion of the housing and then rearwardly into the plug-receiving opening, the conductor structure disclosed in my copending application permits use of much shorter conductors, thus reducing manufacturing and plating costs.
While the connector disclosed in my copending application represents a substantial improvement over previously known connectors, there are features of the device which may be improved upon further. The connector of my copending application cited above includes a portion which is heat-sealed in order to secure the conductors within the housing thereof. It would be desirable to eliminate the need for securing the conductors in this manner. Also, there are certain circuit board mounting applications for which the specific embodiments disclosed in my copending application are not particularly well-suited insofar as physical accessibility of the plug-receiving opening is concerned.